The invention relates to a sealing plug, for example for sealing a hole in the wall of a container for fluid. More particularly, the plug is insertable into the hole, and securable therein, by access only from the outside (i.e. the non fluid-containing side) of the wall. Plugs which are radially expandable into engagement with the surface of the hole are known, for example the type of plug described in GB 2 381 301 B and commercially available under the name AVSEAL II (AVSEAL is a Registered Trade Mark).
In order for the body of the plug to be sufficiently radially expandable in a ductile manner and to a certain extent axially deformable (as described in GB 2 381 301 B), it must be made of a material which is sufficiently soft, e.g. aluminium. However, this has the disadvantage that it restricts the range of fluids which can be contained in the container when its wall has thus been sealed, because the material of the plug body can be subject to attack from certain fluids, for example acids, effluent and some bio-fuels, or subject to erosion, for example via fluid cavitation, or abrasion.
It is an object of the present invention to overcome this disadvantage.
The present invention provides, in one of its aspects, a sealing plug for sealing a hole in a wall, which sealing plug is insertable into the hole by access from only one side thereof, which sealing plug comprises: a radially expandable body which is radially expandable by access thereto from only one end thereof, and a sealing cap which covers the other end of the expandable body and extends therefrom along the exterior of the length of the body, the sealing cap being of a material which is fluid resistant; whereby, when the sealing plug has been inserted in the hole and has been radially expanded so that at least part of the sealing cap adjacent the wall of the hole expands and engages therewith, the sealing cap is secured in the hole with the sealing cap sealing the plug body against access thereto from outside the cap.